What is Convalescent Plasma?
When a person contracts a virus like COVID-19, their immune system creates antibodies to fight the virus. These antibodies are found in plasma, which is the liquid part of blood. Plasma with these infection-fighting antibodies is called “convalescent plasma.” Through a blood donation process, this antibody-rich plasma can be collected from a recovered person, then transfused to a sick patient who is still fighting the virus. This provides a boost to the immune system of the sick patient and may help speed the recovery process.
Is Convalescent Plasma an Effective Treatment for COVID-19?
The FDA has issued an emergency use authorization for the use of COVID-19 convalescent plasma as an investigational treatment for hospitalized patients early in the course of COVID-19 disease if the plasma contains a sufficient quantity of antibodies. The FDA’s emergency use authorization also applies to patients with impaired humoral immunity.
COVID-19 convalescent plasma is often referred to as CCP; when the level of antibodies is high, the units are described as high-titer CCP.
CCP remains an unlicensed, investigational blood product authorized for emergency use because clinical studies have not conclusively shown its effectiveness as a treatment for COVID-19. However, a number of studies have shown that CCP units that do not have a sufficiently high quantity of antibodies (low-titer CCP) may not be beneficial for patients with COVID-19.
We know there is evidence that convalescent plasma has helped patients with other illnesses. There is a continuing debate about whether CCP is an effective treatment for COVID-19; while some studies have been completed, a number of others are still underway.
While additional treatments are evolving, CCP is an option that may help hospitalized patients. The idea to use this treatment for the new coronavirus was suggested by Arturo Casadevall, MD, PhD, from Johns Hopkins University; and Liise-anne Pirofski, MD, from the Albert Einstein College of Medicine.
If you would like to learn more about the literature on CCP, please visit the Resources for Patients section.
A long history of therapy
The collection and transfusion of convalescent plasma as a treatment was first used in the 1890s and helped reduce the severity of a number of infectious disease outbreaks prior to the development of antimicrobial therapy in the 1940s.
In the early 20th century, convalescent plasma treatment was used during outbreaks of various infectious diseases, including measles, mumps and influenza. More recently, it was used during the H1N1 influenza pandemic in 2009, and again in 2013 during the Ebola outbreak in West Africa.